Battery-powered consumer electronics and other low-power devices often include analog front-end circuitry to receive input signal such as voltages or currents for sampling and digital conversion for further analysis or processing. For example, wrist worn electronic devices monitor a user's heart rate and provide an output value indicating a number of beats per minute. An analog front-end circuit receives an analog voltage input signal from a sensor or transducer and on-board processing circuitry digitizes sample values and counts peak values as a function of time to compute a heart rate value for display to the user. Such mixed-signal circuits include both analog and digital circuitry drawing current from a limited-power battery source. Thus, reducing power consumption is an important goal for achieving commercially acceptable overall product size, cost and weight as well as for extending the time between required battery replacements and/or battery charging operations. These goals are also facilitated by reduced memory requirements for the digital circuitry to store obtained digital sample values. Certain battery-powered devices also provide wireless communications capabilities to transfer digital samples to an external host system. Reducing the number of signal samples reduces the wireless bandwidth required to communicate converted signal data values or computed heart rate values and thus further conserves battery power.